Polyazo dyestuffs



Patented May 3, 1938 UNITED STATES PATENT OFFIC'Ei 'Hans Krzikalla and Bernd Eistert, Ludwigshafen-on-theelthine, Germany, assignors to General"Anilinefworks, Inc., New York, N. Y.,

a. corporation of Delaware No Drawing Application October 23, 1936, Se-

rial No. 107,149. In Germany November 8,

9 Claims.

The present invention relates to polyazo dyestuffs.

We have found that new and valuable polyazo dyestu ifs are obtained by first coupling tetrazof tized 2,6'-diamino-l-chlor benzene'e sulphonic acid in acid solution withone molecular propor tion ofa benzene derivative capable of coupling at least twice and then couplingin alkalinesolution with a second molecular proportion of the same or another coupling component; the disazo dyestuiis thus obtained may be converted into trisazo or tetrakisazo dyestuffs by the action of 1 or 2 molecular proportions of a diazo compound or of 2,molecular proportions of different diazo compounds.

As benzene derivatives which are capable of coupling at least twice may bementioned'for, example 1,8-dihydroxybenzene, 1+ rnethyl-2A-dihydroxybenzene, 1,3,5-trihydroxybenzene,1 1,3-dia minobenzene, 1-methyl-2A-diaminobenzene, 1-ni-. tro-2,4 diaminobenzene, 1,3 diaminobenzene-- sulphonic acid, 1,3-diaminobenzene-5,-sulphonic acid and lamino-3-hydroxybenzene. For the conversion of the disazo dyestuffs into trisazo or tetrakisazo dyestuifs there may be used for example diazotized 1 amino 3.; benzenesulphonic acid, 1-amino-4-benzenesulphonic' acid, nitrated or chlorinated aminobenzenes and their sulphonic acids and also aminonaphthalenes and their sulphonic acids.-

The dyestuffs thus obtainable are yellow to redbrown and may be used with advantage "fordyeing leather which is thereby dyed in full, powerful shades of good covering power and" g'oodp'roper ties as regards fastness. The dyestuffs are, however, also suitable for dyeing other fibrous materials, as for example paper or viscose artificial silk.

The process according to this'invention differs from that described in the British Patent No.. 16,811 A. D. 1901 (in which the coupling only takes place in alkaline solution) in that by reason of the coupling in stages, first in acid solution and only then in alkaline solution, the ch l orine atom. of the diaminochlorbenzene sulphonic. acidis not. replaced by a hyroxyl group so that the final dyestuffs still contain chlorine.

The following examples will further illustrate how this invention may be carried out in practice but the invention is not restricted to these examples. The parts are by weight.

Example 1 222.5 parts of 2,6-diamino-1-chlorbenzene-4- sulphonic acid are stirred with 500 parts of concentrated hydrochloric acid and water and tetrazotized with a solution of 138 parts of sodium nitrite in water. A solution of 189 parts of 1,3-diaminobenzen el-sulphonic acid and 120 parts of caustic soda'in water is allowed to flow slowly into the resulting'te'trazo solution. The intermediate; dyestuffseparates from the still acid mixture in the form of a dark red precipitate. This is then stirred into thesolution of 114 parts of 1,3-diam Example 2 Asolutionof parts of 1,3-dihydroxybenzene and 40 ins of caustic soda solution in water is added to atetrazo solution prepared as described in Example land the whole is stirred for an hour.

A solution of 1l0. parts of 1,3-dihydroxybenzene or of 126 parts of 1,3,5-trihydroXybenzene and parts of caustic soda in water is added to the still acidmixture, which thereby becomes alkaline. After coupling is completed, there is stirred into the solution of the disazo dyestufi a diazo solution prepared from 138 parts of l-amincl-nitrobenzene which has been neutralized with sodium acetate. A trisazo dyestufi separates and may be usedas such; it dyes leather red-brown shades. If thetrisazo dyestuff, be dissolved in Water with the addition of thenecessary amount ofsb diu m carbonate and caustic soda solution,

an'da diazo solution prepared from parts of the sodium salt of 1-a.mino-4-benzene sulphonic acid be introduced, a tetrakisazo dyestuff is obtained which yields on leather yellow-brown fast dyeings which cover well.

Example 3 An aqueous solution of 106 parts of 1,3-diaminobenzene is slowly added to a tetrazo solution prepared in the mannerdescr'ibed in Example 1.

1 After 1 hour an aqueous solution of 115 parts of 1,3 diaminobenzene 4 l-chlorbenzenei-sulphonic acids with the following coupling components:

. 2nd coupling com- Shade of color 1st coupling component ponent on leather 1,3-dihydroxybenzene 5,6 dihydro 1,3 di- Yellow-brown;

hydroxybenzene. Do 2 hydroxynaphtha- Red-brown.

lene-fi-sulphonic acid l,3-diaminobenzcne do Violet-brown.

2 hydroxynaphtha- Do.

sulphonic acid. lane l-nitro- 2,4 diaminobenzene.

1,3 diaminobenzene- Brown-yellow. 4-sulph0nic acid. I

What we claim is:- v 1. Polyazo dyestufis corresponding to the general formula wherein A stands for a radicle of the benzene series capable of being coupled atleasttwiee, andv wherein B stands for an aryl radicle capable of being coupled.

2. Polyazo dyestufis correspondingto the general formula sosn wherein A stands for a radicle of the benzene series capable of being coupled at least twice,

wherein B stands for an aryl radicle capable of being coupled and wherein at least one of the radicles A and B contains an azo group. p

3. Polyazo dyestuffs corresponding to the gen eral formula wherein A stands for a radicle of the benzene series capable of being coupled at least twice.. and wherein B stands for an aryl radicle capable of being coupled and X stands for. an aryl radicle.

4. Polyazo dyestufis corresponding to thegeneral formula wherein AiandB stand for radicles of the benzene seriesscapableof being/coupled at least twice.

6. Polyazo dyestuifs corresponding to the general formula wherein Aand B standifor 1,3-dihydroxybenzene radicles capable of being coupled at least twice, and wherein X and Y stand for aryl radicles.

'7. The azo dyestuif corresponding to the formula wherein A stands" for the radicle of 1,3-diaminobenzene-4-sulphonic acid, and'wherein' B stands for the radicle of 1-,3 -diaminobenzene.

8. The azo dyestuff corresponding to the formula wherein-A stands for the radicle of 1,3-dihydroxybenzene.

9. The-azo dyestuff corresponding to the 101'- mula,

wherein A and 3- stand for the radicle of 1,3'-dihydroxybenzen'e';

HANS KRZIKALLA. BERND EISTERT. 

